Various materials have been suggested for imparting flame retardant character to combustible materials U.S. Pat. No. 3,456,041 employs a brominated phosphorus containing material. U.S. Pat. No. 3,642,944 relates to saturated polyester materials which are comprised of reaction products of chlorinated aromatic acids, and dibromoneopentyl glycol. Polyesters containing halogenated phenyl derivatives are described in U.S. Pat. No. 3,772,342. U.S. Pat. No. 3,324,205 teaches flame resistant compositions that are phosphorus containing, as does U.S. Pat. No. 3,830,886. Esters of carbamic acid are taught in U.S. Pat. No. 2,816,910, U.S. Pat. No. 3,391,181 and Belgium Pat. No. 614,347 dated Aug. 23, 1962, reported in Chemical Abstracts 58;3322F.